Check valves are often used in plumbing and piping systems to block the flow of fluid in a particular direction. A common check valve configuration includes a pivoted swinging hanger assembly which carries a valve clapper. The pressure of a fluid in one direction will force open the valve permitting the flow of fluid in that direction. The hanger assembly is mounted in such a way that when fluid pressure in a given direction decreases, gravity causes the valve to close, thereby preventing any fluid from flowing in the opposite direction.
Conventional swing check valve hangers were typically manufactured in one piece, with the valve clapper secured through the use of a threaded stud and nut, or a nut and bolt. This method, however, often prevented the mounting of the valve clapper on the hanger assembly within the desired close tolerances. Merdinyan, U.S. Pat. No. 3,331,391; Munn, U.S. Pat. No. 2,048,943; Long, U.S. Pat. No. 2,454,072; and Anderson et al, U.S. Pat. No. 2,925,827 all utilize a one-piece hanger arm, which necessitated attaching the valve clapper to the hanger arm through the use of a screw or nut, giving rise to problems of inadvertent disassembly from vibration, and difficulties of defining tolerances due to machining inaccuracies. Differences in threading or tightening of the nut made it impossible to define tolerances closely. This often resulted in the valve clapper being mounted loosely to the hanger assembly. Such loose mounting would often result in valve-disc heel hang-ups, closure failures, and mis-alignment or wear of the valve disc. Pfau, U.S. Pat. No. 274,222, employs a one-piece valve clapper, but the hanger arm is also one piece, which requires an additional connecting piece, necessary to attach the valve disc assembly to the hanger arm. Therefore, the problems encountered with two-piece valve clappers are still present.
The present invention utilizes a two-piece hanger assembly, and a one-piece valve clapper which can be manufactured to close tolerances. As there are no nuts, bolts, or threads used, the possibility of valve failure due to loosening of the valve clapper and hanger assembly is eliminated. Tolerances can be maintained to one or two thousandths of an inch, thereby eliminating any chance of valve failure due to sticking or mis-alignment of the valve disc. Costs of manufacture and assembly are also reduced.
Accordingly, it is a principal object of this invention to provide means and apparatus to enable the manufacture of swing-type check valves with closely defined tolerances, and hence eliminating valve failure due to imprecise manufacturing.
It is a further object of this invention to provide increased reliability of swing-type check valves at a reduction in costs of manufacture and assembly.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the features of construction, combinations of elements, and arrangements of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.